High voltage electrical apparatus



Sept. 22, 1936. w. FOSTER HIGH VOLTAGE ELECTRICAL APPARATUS Filed April50, 1935 Inventor Levin W- Foster, by 77 m His Attorneg- Patented Sept.22, 1936 UNITED STATES HIGH VOLTAGE ELECTRICAL APPARATUS Levin W.Foster, Pittsiield, Mass., assignor to General Electric Company, acorporation of New York Application April 30, 1935, Seriai No. 19,001

I 7 Claims. (Ci. 175- 360) My invention relates to high voltageelectrical apparatus, more particularly to high voltage liquid-immersedapparatus such as transformers and reactors. Such apparatus is usuallyenclosed in a metal casing containing a suitable insulating liquid andthe high voltage terminals of the apparatus are brought out of thecasing through suitable insulating bushings. These bushings areexpensive and one of the objects of the-invention is to provide anarrangement which does not require their use. Unless the capacity of theapparatus is very small, its temperature may become excessive duringoperation unless there is some eflicient way of cooling it. Anotherobject of theinvention is therefore to provide an improved arrangementfor carrying away and dissipating the heat generated in the apparatusduring its operation.

Further objects and advantages will be apparent from the followingdescription taken in connection with the accompanying drawing in whichFig. 1 is a view in elevation of a high voltage transformer and meansfor cooling it, the transformer and its cooling means being arranged inaccordance with the invention; Fig. 2 is a plan view of the transformerand its cooling means shown in Fig. l and Fig. 3 shows diagrammaticallythe arrangement of the windings in the transformer.

Like reference characters indicate similar parts of different figures inthe drawing.

The transformer it shown in Fig. 1 includes a series of individualunits, each having three windings M, l2, and it. The windings M are allconnected in series between a high voltage terminal i l and a groundconnection it. The windings i2 and it are connected to form couplingcircuits between the windings i i to assure a uniform distribution ofvoltage throughout the units. The winding it of the unit next to theground connection i5 is provided with terminals it for connection to anexternal low voltage circuit. Each transformer unit surrounded by acylindrical wall of insulating material such as porcelain, these wallsbeing secured together to form a common insulating casing H for thetransformer Iii. The transformer it! with its casing W is mounted on ahollow metal base J8 which may also support some insulating bushings IQfor the 50 low voltage terminals IS. The cover 2d of the easing ll isinsulated from grci'm-d by the casing so that it need not be insulatedfrom the high voltage terminal l4 and this terminal It may therefore bein the form of a simple terminal post.

The transformer I0 is immersed in an insulating liquid 2| which fillsthe casing H and extends through a pipe 22 to a conservator 23 providedwith a breather 26 to permit expansion and contraction of the liquid inthe temperature changes. The pipe 22, which with the conservator 2t andits breather 24 is supported on the cover 29, is connected to andcommunicates with the header at one end of a horizontally disposed metalheat radiator 25. The header at the other end of the radiator 25communicates through and is sup= ported by a pipe 26 which is in turnsupported by a vertical hollow post 27 spaced from the casing I? andmounted on the hollow base 18 with which it communicates also. Theliquid 20 not only fills the casing H but also extends and may circulatethrough the radiator 25, the hollow insulating post 21 and the hollowbase l8, back into the lower end of the casing ill. No insulation isnecessary between the high voltage terminal it and the radiator 25 andconservator 23 because the radiator and conservator are efi'ectlvelyinsulated, as well as supported, by the casing ii and the hollow post2?. Y

The high voltage terminal it is connected by a conductor 28 and aprotective devic'e', such as a fuse 29, to a terminal 39 arranged forconnection to an external high voltage circuit. The hollow post 2i isshown as being formed in sections connected together by liquid-tightjoints and the fuse 2Q is mounted between a support 35 at the top of thepost 2'? and the joint between the upper two sections of the post.

While the transformer i t is in operation, it generates heat which mustbe dissipated to avoid excessive temperature of the transformer. Thisheat is absorbed by the liquid 29 surrounding the transformer, theheated liquid then rising by convection into the radiator 25 where it iscooled, the cooled liquid then descending throughthe hollow post 2i andthen flowing through the hollow base it back into the casing ll, readyto absorb more heat. In the arrangement which has been described, theradiator 25 extends laterally in a more or less horizontal position fromthe upper part of the casing ill, as shown in Fig), 1, so that it iswell exposed to the surrounding ali to which it may dissipate heat veryeffectively. Some additional heat may also be dissipated/oi coursethrough the walls or the post 2i and 'the metal base it.

illustrating a particular arrangement and application thereof but itwill be apparent that changes may be made without departing from thespirit of the invention and the scope of the post spaced from saidcasing and supporting and communicating with the other end of saidradiator, means providing communication between the lower ends of saidcasing and post, and an insulating liquid in said casing, radiator andpost.

2. The combination with electrical apparatus of an insulating casingtherefor, a hollow insulating support spaced from said casing, a metalheat radiator supported by the upper ends of said casing and support,means providing communication between the lower ends of said casing andsupport, and an insulating liquid in said casing, radiator and support.I

3. The combination with electrical apparatus of an insulating casingtherefor, a hollow base supporting and communicating with said casing, ahollow insulating support spaced from said casing and mounted on andcommunicating with said base, a metal heat radiator supported by andproviding communication between the upper ends of said casing andsupport, and an insulating liquid in said casing, radiator, support andbase.

4. The combination with electrical apparatus of an insulating casing, ahollow insulating support spaced from said casing, means providingcommunication between the lower ends of said casing and support, a metalheat radiator supported substantially horizontally by and communicatingwith the upper ends of said casing and support, and an insulating liquidin said casing, radiator and support.

5. The combination with electrical apparatus of an insulating casingtherefor, a high voltage terminal for said apparatus on the upper end ofsaid casing, a hollow insulating support spaced from said casing, ametal heat radiator supported by and providing connection between theupper ends of said casing and support, means providing communicationbetween the lower ends of said casing and support, a protective deviceand a terminal mounted on said support, and connected to said highvoltage terminal, and an insulating liquid in said casing, radiator andsupport.

6. The combination with electrical apparatus of an insulating casingtherefor, a metal heat radiator extending laterally from the upper partof said casing and communicating therewith, the end of said radiatoradjacent the casing being supported thereby, an insulating support forthe other end of the radiator, and an insulating liquid in said casingand radiator. Y

7. The combination with electrical apparatus of an insulating casingtherefor, a metal heat radiator extending laterally from the upper partof said casing and supported at one end thereby, said radiatorcommunicating with the upper part of said casing, insulating meanssupporting the other endof said radiator providing communication betweensaid radiator and the lower part of said casing, and an insulatingliquid in said casing and radiator.

' i "LEVIN W. FOSTER.

